Automatic-safety-gates for freight-elevators.



G. W. UNDERWOOD. AUTOMATIC SAFETY GATES FOR FREIGHT ELEVATORS.

APPLICATION FILED MAR.29,1911.

1,035,759. Patented Aug. 13,1912.

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GEORGE W. UNDERWOOD, OF COUNCIL BLUFFS, IOWA.

AUTOMATIC SAFETY-GATES FOR FREIGHT-ELEVATORS.

Specification of Letters Patent.

Patented Aug. 13, 1912.

Application filed March 29,, 1911. Serial No. 617,793.

To all whom it may concern.

Be it known that I, GEORGE W. UNDER- Woon, a citizen of the UnitedStates, residing at Council Bluffs, in the county of Pottawattamie,State of Iowa, have invented certain new and useful Improvements inAutomatic Safety-Gates for Freight-Elevators, of which the following isa specification.

My invention relates to improvements in new and useful devices wherebythe safety gates of an elevator are operated by the passage of theelevator car, and my object is to provide novel devices of thischaracter which are simple in construction and operatain, and not liableto get out of order.

Other objects of the invention will hereinafter appear and in order thatsaid invention may be fully understood, reference will now be made tothe accompanying drawing, in which:

Figure 1 is a vertical section of an elevator shaft, the elevator carand the gates. Fig. 2 is a broken front elevation of the parts shown inFig. 1, with the gates removed. Fig. 3 is a broken detail frontelevation of a sprocket-chain employed in carrying out the invention,and Fig. 4 is a broken detail side elevation of a propelling chainforming part of the invention.

The same letters of reference are used to indicate identical parts inall the figures.

A designates a freight elevator car; B one of the guide-posts for thecar; D two floors of a building, and a-a the safety gates to guard thehatchways of the respective floors, but one pair of gates being shownfor the lower floor in the present instance.

Two cables 6-6 are attached at one end to their respective gates a-a andat their other end to an eye-bolt T, secured to a counterweight K, whichassists the elevator car A to raise the gates aa and thus relieve theseveral parts of the device of the major portion of the weight of saidgates and the friction incident to raising the same. Cables 6-4) intheir passage from the gates aa to the counterweight K run overguide-sheaves 00 and SS, the former being supported from the upper floorD, while the latter are loosely-mounted upon a shaft L, mounted in apair of brackets m projecting from the adjacent guide posts B. Shaft Lis provided with a loosely-mounted sprocket-wheel f, arranged betweenthe brackets m, over which an endless, propelling sprocket-chain E runs,said propelling sprocket-chain running beneath a sprocketwheel F.Sprocket-wheel F is keyed upon a shaft G mounted in a tightener P-R,secured to the guide'post B to take up slack in the propelling-chain Eand a sprocketchain 2', hereinafter referred to. The sprocket-chain 2'has a link J provided with a laterally-projecting stud upon which thecounterweight K is mounted. Propelling chain E is provided withforwardly projecting lugs (Z and (Z spaced a short distance apart toreceive the outturned terminal of an arm 0, projecting from the upperportion of one side of the elevator car A for the purpose of actuatingthe propelling chain E, as will hereinafter appear.

H designates a large sprocket-wheel keyed upon shaft Gr beside the smallsprocketwheel F and operablyconnected through the intermediacy ofsprocket-chain 2' to another large sprocket-wheel h, loosely-mountedupon a stub-shaft O, projecting laterally from a bracket N, secured toguide-post B, intermediate the brackets on and the tightener P R whichare located near the upper and lower floors, respectively.

Operation: As the elevator car A travels from the lower floor D to theupper floor D, arm C engages lug (Z and carries the same upward untilit, through the intermediacy of the propelling chain E, movescounterweight K to the right from its position at the deadcenterextending vertically through the axis of the sprocket-wheel TI. As thecounterweight K moves outward to the right from said dead-center, it isdrawn upward by the descending gates aa, which are heavier than saidcounterweight and draw the same upward to the dotted position shown onFig. 1. As the counterweight K is drawn upward, it, through theintermediacy of the intervening mechanism actuates the propelling chainE until the lugs (Z and (Z are carried upward to the dotted positionshown on Fig. 1, at which time the gates a a reach closed position. Asthe gates move downward to closed position they are retarded by lug (Zwhich is drawn up into engagement with arm C, thus it will be understoodthatthe gates cannot descend more rapidly than the elevator car ascends.When the elevator car descends from the upper floor D to the lower floor1), arm C engages lug (Z and carries the same downward, so that it,through the intermediacy of the intervening mechanism, will draw thegates aa, upward to open position.

Having thus described my invention what I claim and desire to secure byLetters Patent, is:

1. In combination with an elevator gate and an elevator car, acounterweight to assist in raising said gate to open position, asuitably-guided cable attached at its ends to the gate and saidcounterweight, a chain carrying the counterweight, a propelling chaingeared to the first-mentioned chain to actuate the same, two lugs spaceda short distance apart on said propelling chain, and an arm on theelevator car adapted to engage one of said lugs and move the propellingchain in one direction to open the elevator gate and engage the otherlug to move the propelling chain in a reverse direction to close thegate, substantially as described.

2. In combination with a pair of elevator gates and an elevator car, acounterweight to assist in raising said gates to open position,suitably-guided cables attached at their ends to the gates and saidcounterweight, an endless sprocket-chain carrying said counterweight, apair of sprocket-wheels around which said sprocket-chain extends,

an endless propelling sprocket-chain, a pair of sprocket-Wheels aroundwhich said propelling chain extends, a journaled shaft upon which one ofthe sprocket-wheels for each chain is keyed so that the propelling chainmay actuate the first-mentioned chain,

a pair of lugs spaced a short distance apart and projecting from oneside of the propelling sprocket-chain, and an arm carried by theelevator car and adapted to engage one of said lugs to move thepropelling-chain in Copies of this patent may be obtained for five centseach, by addressing the Commissioner of Patents. Washington, D. G.

